Cadmoselite is a rare cadmium selenide mineral with

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

CdSe. Cadmoselite crystallizes in the

hexagonal In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...

system and occurs as black to pale grey opaque crystals and grains.http://rruff.geo.arizona.edu/doclib/hom/cadmoselite.pdf Handbook of Mineralogyhttp://webmineral.com/data/Cadmoselite.shtml Webmineral data

It was first described in 1957 for an occurrence in

Tuva Tuva (; russian: Тува́) or Tyva ( tyv, Тыва), officially the Republic of Tuva (russian: Респу́блика Тыва́, r=Respublika Tyva, p=rʲɪˈspublʲɪkə tɨˈva; tyv, Тыва Республика, translit=Tyva Respublika ...

. The mineral occurs as interstitial grains in

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...

formed under reducing

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

diagenetic conditions.

References

*Emsley, John. ''Nature's Building Blocks.'' Oxford, 2001. Cadmium minerals Selenide minerals Hexagonal minerals Minerals in space group 186 {{Mineral-stub